논리 연산자는 두 개 이상의 표현식이나 조건을 결합하여 주어진 표현식에 대해 논리 연산을 수행합니다. 다양한 관계식과 조건식에 사용될 수 있습니다. 이 연산자는 조건을 논리적으로 확인하기 위해 Boolean 값을 기반으로 하며, 조건이 true이면 1을 반환하고, 그렇지 않으면 0(False)을 반환합니다. C 프로그래밍에서 논리 연산자는 논리 AND(&&) 연산자, 논리 OR 연산자(||), 논리 NOT(!) 연산자의 세 가지 유형으로 분류됩니다. 여기서는 논리 AND 연산자와 C 프로그래밍 언어의 다양한 예에 대해 알아봅니다.
논리 AND 연산자
논리 AND 연산자는 '&&' 이중 앰퍼샌드 기호로 표시됩니다. 두 개 이상의 피연산자의 조건을 표현식으로 결합하여 확인하고, 모든 조건이 true이면 논리 AND 연산자는 불리언 값 true 또는 1을 반환하고, 그렇지 않으면 false 또는 0을 반환합니다.
DBMS의 산성 속성
참고: 두 값이 모두 0이 아닌 경우 조건은 true로 유지됩니다. 그렇지 않으면 논리 AND(&&) 연산자는 0(false)을 반환합니다.
통사론
(condition1 && condition2)
위 구문에는 조건1과 조건2라는 두 가지 조건이 있으며 그 사이에는 이중(&&) 앰퍼샌드 기호가 있습니다. 두 조건이 모두 true이면 논리 AND 연산자는 부울 값 1 또는 true를 반환합니다. 그렇지 않으면 false를 반환합니다.
논리 AND(&&) 연산자의 진리표
| ㅏ | 비 | A && B |
|---|---|---|
| 1 | 1 | 1 |
| 1 | 0 | 0 |
| 0 | 1 | 0 |
| 0 | 0 | 0 |
예제 1: C의 논리 AND 연산자를 시연하는 프로그램
#include #include int main () { // declare variable int n = 20; // use Logical AND (&&) operator to check the condition printf (' %d
', (n == 20 && n >= 8)); // condition is true, therefore it returns 1 printf (' %d
', (n >= 1 && n >= 20)); printf (' %d
', (n == 10 && n >= 0)); printf (' %d
', (n >= 20 && n <= 40)); return 0; } < pre> <p> <strong>Output</strong> </p> <pre> 1 1 0 1 </pre> <p> <strong>Example 2: Program to find the largest number using the Logical AND operator</strong> </p> <pre> #include #include int main () { // declare integer type variable int x, y, z; printf (' Enter the first number: '); scanf ('%d', &x); printf (' Enter the second number: '); scanf ('%d', &y); printf (' Enter the third number: '); scanf ('%d', &z); // use logical AND operator to validate the condition if ( x >= y && x >= z ) { printf (' %d is the largest number of all. ', x); } else if ( y >= x && y >= z) { printf (' %d is the largest number of all. ', y); } else { printf ( ' %d is the largest number of all. ', z); } return 0; } </pre> <p> <strong>Output</strong> </p> <pre> Enter the first number: 20 Enter the second number: 10 Enter the third number: 50 50 is the largest number of all </pre> <p> <strong>Example 3: Program to use the Logical AND (&&) operator to check whether the user is teenager or not.</strong> </p> <pre> #include #include int main () { // declare variable int age; printf (' Enter the age: '); scanf (' %d', &age); // get age // use logical AND operator to check more than one condition if ( age >= 13 && age <= 19) { printf (' %d is a teenager age. ', age); } else not return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter the age: 17 17 is a teenager age. 2nd execution: Enter the age: 10 10 is not a teenager age. </pre> <p> <strong>Example 4: Program to validate whether the entered number is in the defined range or not.</strong> </p> <pre> #include int main () { int num; printf (' Enter a number between 1 to 50: '); scanf (' %d', &num); //get the number // use logical AND operator to check condition if ( (num > 0 ) && (num 50 ) && ( num <= 50 100)) { printf (' the entered number is in range and 100. '); } else please enter defined range. return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a number between 1 to 50: 19 The entered number is in the range 0 and 50. 2nd Run Enter a number between 1 to 50: 51 The entered number is in the range 50 and 100. 3rd execution: Enter a number between 1 to 50: 0 Please enter the number is in the defined range. </pre> <p> <strong>Example 5: Program to validate the username and password entered by the user is correct or not using the predefined username and password.</strong> </p> <pre> #include #include // use #define macro to define the values for UserName and Password #define UserName 'system' #define Password 'admin@123' int main () { // declare character type array char un[50], pass[50]; // take UserName and Password from user printf ( ' Enter the username: ' ); scanf (' %s', un); printf ( ' Enter the password: ' ); scanf (' %s', pass); // use if statement and Logical AND operator to validate the condition if (strcmp (UserName, un) == 0 && strcmp (Password, pass) == 0) { printf ('
The user's credentials are correct. '); } else { printf ( '
The user's credentials are incorrect. '); } return 0; } </pre> <p> <strong>Output</strong> </p> <pre> Enter the username: system Enter the password: admin@123 The user's credentials are correct. 2nd execution Enter the username: system Enter the password: admin@1234 The user's credentials are incorrect. </pre> <hr></=></pre></=></pre></=> 예제 2: 논리 AND 연산자를 사용하여 가장 큰 숫자를 찾는 프로그램
#include #include int main () { // declare integer type variable int x, y, z; printf (' Enter the first number: '); scanf ('%d', &x); printf (' Enter the second number: '); scanf ('%d', &y); printf (' Enter the third number: '); scanf ('%d', &z); // use logical AND operator to validate the condition if ( x >= y && x >= z ) { printf (' %d is the largest number of all. ', x); } else if ( y >= x && y >= z) { printf (' %d is the largest number of all. ', y); } else { printf ( ' %d is the largest number of all. ', z); } return 0; } 산출
Enter the first number: 20 Enter the second number: 10 Enter the third number: 50 50 is the largest number of all
예제 3: 논리 AND(&&) 연산자를 사용하여 사용자가 청소년인지 여부를 확인하는 프로그램입니다.
#include #include int main () { // declare variable int age; printf (' Enter the age: '); scanf (' %d', &age); // get age // use logical AND operator to check more than one condition if ( age >= 13 && age <= 19) { printf (\' %d is a teenager age. \', age); } else not return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter the age: 17 17 is a teenager age. 2nd execution: Enter the age: 10 10 is not a teenager age. </pre> <p> <strong>Example 4: Program to validate whether the entered number is in the defined range or not.</strong> </p> <pre> #include int main () { int num; printf (' Enter a number between 1 to 50: '); scanf (' %d', &num); //get the number // use logical AND operator to check condition if ( (num > 0 ) && (num 50 ) && ( num <= 50 100)) { printf (\' the entered number is in range and 100. \'); } else please enter defined range. return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a number between 1 to 50: 19 The entered number is in the range 0 and 50. 2nd Run Enter a number between 1 to 50: 51 The entered number is in the range 50 and 100. 3rd execution: Enter a number between 1 to 50: 0 Please enter the number is in the defined range. </pre> <p> <strong>Example 5: Program to validate the username and password entered by the user is correct or not using the predefined username and password.</strong> </p> <pre> #include #include // use #define macro to define the values for UserName and Password #define UserName 'system' #define Password 'admin@123' int main () { // declare character type array char un[50], pass[50]; // take UserName and Password from user printf ( ' Enter the username: ' ); scanf (' %s', un); printf ( ' Enter the password: ' ); scanf (' %s', pass); // use if statement and Logical AND operator to validate the condition if (strcmp (UserName, un) == 0 && strcmp (Password, pass) == 0) { printf ('
The user's credentials are correct. '); } else { printf ( '
The user's credentials are incorrect. '); } return 0; } </pre> <p> <strong>Output</strong> </p> <pre> Enter the username: system Enter the password: admin@123 The user's credentials are correct. 2nd execution Enter the username: system Enter the password: admin@1234 The user's credentials are incorrect. </pre> <hr></=></pre></=> 예제 4: 입력된 숫자가 정의된 범위에 있는지 여부를 확인하는 프로그램입니다.
#include int main () { int num; printf (' Enter a number between 1 to 50: '); scanf (' %d', &num); //get the number // use logical AND operator to check condition if ( (num > 0 ) && (num 50 ) && ( num <= 50 100)) { printf (\' the entered number is in range and 100. \'); } else please enter defined range. return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a number between 1 to 50: 19 The entered number is in the range 0 and 50. 2nd Run Enter a number between 1 to 50: 51 The entered number is in the range 50 and 100. 3rd execution: Enter a number between 1 to 50: 0 Please enter the number is in the defined range. </pre> <p> <strong>Example 5: Program to validate the username and password entered by the user is correct or not using the predefined username and password.</strong> </p> <pre> #include #include // use #define macro to define the values for UserName and Password #define UserName 'system' #define Password 'admin@123' int main () { // declare character type array char un[50], pass[50]; // take UserName and Password from user printf ( ' Enter the username: ' ); scanf (' %s', un); printf ( ' Enter the password: ' ); scanf (' %s', pass); // use if statement and Logical AND operator to validate the condition if (strcmp (UserName, un) == 0 && strcmp (Password, pass) == 0) { printf ('
The user's credentials are correct. '); } else { printf ( '
The user's credentials are incorrect. '); } return 0; } </pre> <p> <strong>Output</strong> </p> <pre> Enter the username: system Enter the password: admin@123 The user's credentials are correct. 2nd execution Enter the username: system Enter the password: admin@1234 The user's credentials are incorrect. </pre> <hr></=> 예제 5: 사용자가 입력한 사용자 이름과 비밀번호가 올바른지 확인하는 프로그램이 사전 정의된 사용자 이름과 비밀번호를 사용하고 있지 않은지 확인합니다.
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#include #include // use #define macro to define the values for UserName and Password #define UserName 'system' #define Password 'admin@123' int main () { // declare character type array char un[50], pass[50]; // take UserName and Password from user printf ( ' Enter the username: ' ); scanf (' %s', un); printf ( ' Enter the password: ' ); scanf (' %s', pass); // use if statement and Logical AND operator to validate the condition if (strcmp (UserName, un) == 0 && strcmp (Password, pass) == 0) { printf ('
The user's credentials are correct. '); } else { printf ( '
The user's credentials are incorrect. '); } return 0; } 산출
Enter the username: system Enter the password: admin@123 The user's credentials are correct. 2nd execution Enter the username: system Enter the password: admin@1234 The user's credentials are incorrect.